This invention relates generally to apparatus for maintaining the proper tension in a drive belt, and more particularly to apparatus for maintaining the proper tension in a drive belt used to provide reciprocal movement to optical scanning apparatus.
There are numerous scanning apparatuses on the market today which comprise a frame having a transparent document supporting plate mounted thereon for supporting a document to be scanned and scanning apparatus mounted beneath the transparent document supporting plate for reciprocal linear movement relative to the transparent document supporting plate. The apparatus for providing the reciprocal movement for the scanning apparatus generally comprises at least two spaced apart pulleys mounted on the frame wherein one of the spaced apart pulleys is periodically rotated in opposite directions. A drive belt is connected to the scanning apparatus and is journaled around the spaced apart pulleys and has opposite end portions connected to the scanning apparatus so that rotation of the one pulley in opposite directions provides reciprocal linear movement to the scanning apparatus. At the present time, at least one of the at least two spaced apart pulleys is mounted on the frame so that it may be moved over the frame relative to the other of the at least two spaced apart pulleys until the proper tension is provided in the drive belt and then secured to the frame. However, after numerous reciprocations of the scanning apparatus, the tension in the drive belt is reduced and malfunctioning of the scanning apparatus occurs. Variations in belt tension may also be produced by changes in temperature and humidity. Therefore, there is a need to provide apparatus for maintaining the proper tension in the drive belt.
Patents disclosing scanning apparatus include U.S. Pat. No. 5,044,727 of Steinle and U.S. Pat. No. 5,019,703 of Boyd et al., which are both hereby specifically incorporated by reference for all that is disclosed therein.